1. Technical Field
The present invention relates to thermal interface materials, and more particularly to an apparatus for making thermal interface material.
2. Description of the Related Art
In recent years, with the ongoing development of electronic technology, semiconductor devices have increased both in their operating frequency and speed, with ever smaller miniaturization and packaging. Heat dissipation has thus become an important problem for semiconductor devices. In order to solve the problem, some heat sinks, such as heat fans, water-cooling devices, and heat pipes, are used to dissipate the heat. Thermal interface material is also used between the heat sink and the semiconductor device to increase efficiency of heat dissipation.
In order to obtain high thermal conductivity, some particles with high thermal coefficient, such as graphite, boron nitride, aluminium oxide, or silver, are mixed with a polymer compound to make a composite thermal interface material.
Referring to FIG. 1, a typical apparatus 1 for making thermal interface material is shown. The apparatus 1 includes a container 2 and a stirrer 3 operating in the container 2. The stirrer 3 generally uses a plurality of distal vanes 4 to stir a matrix material 5 and thermal particles 6 in the container 2. When using the apparatus 1 to make the thermal interface material, the matrix material 5 and the thermal particles 6 are put into the container 2. The stirrer 3 rotates along with the distal vanes 4, and then the distal vanes 4 stir the matrix material 5 and the thermal particles 6 to make thermal interface material.
However, when the mass of the thermal particles 6 is larger than that of the matrix material 5, the thermal interface material has a high viscosity. Thus when the apparatus 1 is used to mix the proportion above of the matrix material 5 and the thermal particles 6, the matrix material 5 and the thermal particles 6 adhere to the stirrer 3. Thus the stirrer 3 hardly stirs the matrix 5 and the thermal particles 6 and the apparatus 1 cannot operate normally. Therefore, the matrix material 5 and thermal particles 6 are not mixed uniformly so that high thermal conductivity of the interface material is not achieved.
What is needed, therefore, is an apparatus for making thermal interface material that can mix the matrix material uniformly with the thermal particles having larger mass than that of the matrix material.